In krill (which belongs to the order Euphausiaceae), a mixture of different enzymes exists, such as e.g. proteinases (with acidic and neutral-to-alkaline pH-optimum), peptidases (exo- and endopeptidases), lipases, phospholipases, amylases and other carbohydrate degrading enzymes, phosphatases, nucleases, nucleotidases and esterases (T. E. Ellingsen; Biokjemiske Studier over Antarktisk Krill; Dr. ing avhandling; Institutt for Teknisk Biokjemi, Norges Tekniske Hogskole, Trondheim (1982). The proteolytic (trypsin-like) activity existing in a water extract from krill has been studied and described (C.-S. Chen et al; J. Food Biochem. 2 (1978) p. 349-66)). Different protease activities in water extracts from capelin have also been described previously (A Gildberg; Autolysis of fish tissue--General aspects; Thesis; Institute of Fisheries; University of Tromso Norway (1982)).
As early as 1913 proposals were made to use enzymes in detergents. Enzyme compositions for cleaning of dead materials, e.g. as laundry agents, have previously been based on different microbial proteases from the genus Bacillus. One such protease commonly used is subtilisin derived from Bacillus subtilis strains and marketed among others under the name Alcalase.RTM. (Novo Industri, Copenhagen, Denmark). Different lipases have also been used for cleaning, especially for enabling degradation of lipids. In addition to enzymes, such compositions have contained also different anionic, cationic and neutral detergents together with blanchophores, such as perborates. The enzymes used hitherto have, like enzymes in general, been relatively unstable.
The most important enzyme compositions on the market for debridement of the components mentioned above are Streptokinase-streptodornase (Varidase.RTM., Lederle Lab., American Cyanamid Company, Wayne, N.J., USA), stabilized crystalline trypsin (Trypure.RTM., Novo Industri, Copenhagen, Denmark) and bovine fibrinolysin combined with deoxyribonuclease (Elase.RTM., Parke Davis & Company, Detroit, Mich., USA). Streptokinase acts on necrotic material mainly by its effect on DNA and streptodornase has a specific fibrinolytic effect. Trypsin acts proteolytically and is extracted from bovine pancreas. Fibrinolysin-deoxyribonuclease in a combination of two enzymes--one fibrin degrading enzyme and one acting on deoxyribonucleic acid which is an important component in pus.
One specific pepsin-like enzyme (pepsin I) from Mallotus villosus (capelin) has been proposed to be used in the medical treatment of burns (Gildberg A; cited above p. 89-90). The use of one specific enzyme acting on one type of substrates is likely to achieve only a limited breakdown of the contaminants present in wounds. However, no combination of this pepsinlike enzyme with other enzymes has been proposed for the therapeutical cleaning of humans.
The enzyme preparations mentioned above suffer from several drawbacks. Thus, all of them are relatively unstable leading to a rapid decrease in their activity, either during storage or use. Their activities are often limited to a certain pH-range, e.g. neutral to moderately alkaline pH. Their activities are also in many cases restricted to certain temperature intervals. At a temperature above +50.degree. C., a rapid loss of activity is observed and at room temperatures or normal outdoor temperatures, their activities are low.
The effect of Varidase.RTM., Trypure.RTM. and Elase.RTM. are relatively poor for its purpose. Only a moderate debriding effect is usually achieved after a treatment over a period of three weeks.